Apparatus for the control of highway crossing signals



Feb. 11, 1936. J, A, PARKINSON APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Filed April 24, 1935 INVENTOR JameJ/U arkinSQn.

J \YFME 3 Ir 7 9% kl 3 3 fi j MSM an N h m? 5 Q aw :6 1%

BY I: 3.4 HISATTORNEY Patented Feb. 11, 1936 NETE STATES PATENT OFFICE APPARATUS FOR- THE CONTROL OF HIGH- WAY CROSSING SIGNALS Application April 24,

15 Claims.

My invention relates to apparatus for the control of highway crossing signals, and has for an object the provision of apparatus controlled by a train approaching a highway crossing for starting the operation of the signal at substantially the same interval of time before the train reaches the crossing regardless of the speed of the train. Other objects and advantages of my invention will appear as the specification progresses.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

For a better understanding of my invention reference may be had to the accompanying drawing which is a diagrammatic view of a preferred embodiment of the invention. Referring to the drawing, the reference characters A l and i la designate the track rails of a stretch of railway over which traffic normally moves in the direction indicated by an arrow and which stretch is intersected at grade by a highway H. A highway crossing signal W is located adjacent the intersection and. is indicated on the drawing conventionally by the symbol commonly used in the art to designate a wigwag signal. As is common practice, this signal W is set to be plainly exhibited to highway users approaching the intersection from both directions, the arrangement being such that when operating current is supplied to the operating mechanism SM a warning is displayed to the highway users by a swinging disc with preferably a red light attached, but that when operating current is not supplied to the mechanism. SM, the disc and light are concealed from View. It will be understood, of course, that other forms of highway crossing signals may be used if desired.

As here shown, the track rails H and Ho are divided by the usual insulated rail joints to form two track sections XY and YZ, which sections are traversed successively in the order named by a train approaching the highway I-I when. moving in the normal direction of traffic.

track section is provided with a track circuit comprising a battery to connected across the track rails at one end of the section and a track relay designated by the reference character TR plus an exponent corresponding to the location connected across the rails at the other end of the section. For the purpose of this description, I shall refer to the track section XY as a timing or measuring section, and to the section YZ as an operating section. As will appear hereinafter, the time consumed by a train in passing through the timing section XY is measured and hence 1935, Serial No. 17,974

the speed of the train is registered, and the highway crossing signal Wis set then into operation in accordance with this registered speed after the train has entered the operating section YZ.

In order tomore easily understand the apparatus embodying myinvention, I shall assume a maximum speed for all trains approaching the highway H of 80 miles per hour, and an operating time for the signal W of at least 20 seconds and not more than seconds prior-to the arrival of a train at the crossing, except in the case of a train whose speed is below a predetermined low speed which I shall assume to be 13 miles per hour. A train traveling at 80 miles per hour advances approximately 2350 feet in 20 seconds, hence the operating section YZ is preferably slightly greater than 2350 feet, say 2400 feet,in length since the signal W is not set into operation until a train enters this operating section and since at least 20 seconds ope-ration of the signal prior to the arrival of the train at the crossing is desired. A train traveling at 54 miles per hour advances approximately 2380 feet in 30 seconds. It follows that for all trains having a speed above 54 miles per hour and the signal W set into operation immediately upon the train entering the operating section YZ, the operating time of the signal'prior to the arrival ofthe train at the crossing is not less than 20 seconds and is not more than 30 seconds, and which intervals correspond to the assumed permissible variation in the operating time. The timing or measuring section XY may be of any convenient length and is preferably of the same length as the op erating section. In the present case I shall assume the timing section XY tobe substantially 2400 feet in length. It will be understood, of course, that my invention is not limited to the above stated values of train speeds, lengths of track sections and operating intervals ofthe highway crossing signal and such'values may be selected best suited for the location at which the apparatus is installed.

The operation of the mechanism SM and hence the operation of the signal'W is controlled by an interlocking relay IRof the usual type, the arrangement being such that so long as the left-hand winding 9 of the relay IR is deenergized and its armature I2 is in engagement with a full down contact 13, the operating mechanism SM is supplied with current from any convenient source such as a'-battery not shown over a simple circuit easily traced, .and the signal W is operated todisplay a warning to the highway users, but that at such time-as the winding '9 is energized and the armature I2 is lifted out of engagement with the contact I3, operating current is not supplied to the mechanism SM and the signal W is inactive. In accordance with usual practice the right-hand winding I4 of the relay IR may also govern the operation of the signal W in response to traffic approaching the highway H against the normal direction of traffic, but such control is not shown since it forms no part of my present invention.

The left-hand winding 9 of the relay IR is normally energized over a simple circuit which includes a front contact I6 of the track relay 2TB of the operating section YZ as will be readily understood by an inspection of the drawing. Hence, as long as the track section YZ.

is unoccupied and the track relay ZTR. is picked up, the highway crossing signal W is inactive, but that when the relay ZTR is shunted in response to a train occupying the section YZ, the winding 9 of the relay IR is deenergized and the signal W is set into operation unless the winding 9 is retained energized over a circuit network to be described hereinafter and which circuit network includes a back contact I! of the relay ZTR.

A repeater relay TPR is preferably associated with the track relay YTR of the timing section XY, the arrangement being such that the repeater relay TPR is energized over a circuit including line wire I8 and the front contact I9 of the relay YTR. It follows that as long as the timing section XY is unoccupied and the track relay YTR is picked up, the repeater relay TPR is also picked up, but that shunting of the track relay YTR in response to a train occupying the section XY causes the relay TPR to be released. The function of the relay TPR will appear hereinafter.

Certain of the circuit controlling armatures of the relays ZTR and TPR are shown located remote from the winding of their relay in order to simplify the drawing as much as possible. In each such instance the armature is identified by the reference character corresponding to the relay controlling that armature plus a distinctive reference numeral and the armature is illustrated in the position corresponding to the condition of the relay. For example, the armature ZTRZU is operated by the track relay ZTR and this armature is shown lifted out of engagement with its back contact 2| since the relay ZTR is normally energized.

The apparatus includes a control mechanism designated as a whole by the reference character CM and which is operative to register the speed of a train approaching the highway H by determining the time consumed by the train in passing through the timing section XY, and to subsequently govern the setting of the signal W into operation while the train occupies the operating section YZ. This control mechanism CM comprises a first and a second time measuring means designated as a whole by the reference characters TMI .and TMZ, respectively, and each of which includes a series of individual timing units. The timing units may be of any convenient type and, as here shown, the timing units of the first time measuring means TMI each comprises a thermal relay and a stick relay, the thermal relays being of the type where current supplied to .a heating element is effective to close a normally open contact after a predetermined time interval, and the associated stick relays being of the direct current neutral type.

In the present instance nine such timing units are provided, the respective thermal relays being designated by the reference characters IT, 2T, 3T, 4T, 5T, 6T, IT, 8T and ST, and the respective stick relays being designated by the reference characters IS, 2S, 38, 4S, 5S, 68, IS, 88 and BS. The second time measuring means TM2 consists of nine individual timing units which are designated by the reference characters ID, 2D, 3D, 4D, 5D, 6D, ID, 8D and 9D. These D timing units may be thermal relays similar to the thermal relays of the first time measuring means except for the fact that a normally closed circuit controlling contact is operated to an open position in a predetermined time interval, whereas the T relays of the first time measuring means are adjusted to close a contact in a predetermined time interval. These D timing units may be time element relays of the type disclosed .and claimed in the United States Letters Patent No. 1,966,965, issued July 17, 1934, to Branko Lazich and H. E. Ashworth, for Electrical relays. The individual timing units of each time measuring means are in this instance so proportioned and adjusted that operation of the respective contact is in accordance with the time indicated on the drawing, it being understood, of course, other adjustments may be made for other track and speed conditions.

The control of the thermal relay T and the stick relay S of each timing unit of the first time measuring means TMI is similar for each unit and it is thought that a description of the control of the relays for the first two units will be sulficient for an understanding of all. ring to the relays IT and. IS of the first timing unit, a heating circuit for the relay IT may be traced from the B terminal of the current source over front contact 24 of the track relay ZTR, wire 25, terminal post 6 of the control mechanism CM, wire 26, back contacts 21, 28, 29, 30, 3|, 32, 33, 34, and of the successive stick relays 9S to IS, inclusive, wire 36, heating element 22 of relay IT, a second terminal post I of the mechanism CM, wire 37, back contact 38 of the repeater relay TPR and to the opposite terminal C of the same source of current. The relay IT is adjusted to operate its contact 23 in substantially 30 seconds, and the contact 23 when closed completes a pickup circuit for the stick relay IS and that relay is energized, this pickup circuit extending from the B battery terminal over contact 23, winding of relay IS, back contact 41 of the next succeeding stick relay 2S and thence to the 0 battery terminal. The picking up of the stick relay IS accomplishes four things, namely, closes its own stick circuit, completes the heating circuit for the next succeeding thermal relay 2T, opens the circuit for the heating element of the associated thermal relay IT and closes a normally open contact in the circuit network for the winding 9 of the interlocking relay IR. The

' first three things accomplished by the energizing of the relay IS will now be described but the function of the contact of relay IS which is interposed in the circuit network will be taken up when the operation of the apparatus is described.

The stick circuit for the relay IS includes the B battery terminal, back contact 39 of the circuit controlling armature TPRAQ, wire 4|, terminal post 'I of the control mechanism CM, wire 46, front contact 43 of a relay 42 to be referred to later, wire 44, front contact 45 of relay IS, winding of that relay, back contact 41 of the relay 2S and to the C battery terminal. It is to be noted Refers that this stick circuit for the relay IS may be completed over the back contact 48 of the circuit controlling armature ZTRAS, the two back contacts 39 and 48 being in parallel. It is clear, therefore, that in response to a train entering the timing section XY and'shunting the track relay YTR, current is supplied to the heating element of the relay IT if the operating section YZ is unoccupied and its track relay ZTR is picked up, and if the stick relays 95 to IS, inclusive, are in a normal deenergized position as illustrated in the drawing. In the event seconds elapses before the train advances through the timing section X-Y and enters the operating section Y-Z, the contact 23 of relay IT is operated and the stick relay IS is picked up and then held energized over its stick circuit as long as the train occupies either of the sections XY or Y--Z and one or both of the back contacts 39 or 40 are closed, unless, in the meantime, the next succeeding stick relay 2S is picked up and its back contact 47 is opened, or unless the relay 42 is released and its front contact 43 is opened.

The closing of the front contact of relay IS completes the circuit for the heating element 5I of the next thermal relay 2T, the circuit being traced from the B battery terminal over the same circuit elements included in the circuit for the heating element 22 of the relay IT up to the back contact 34 of relay 2S, thence over wire 52, heating element 5| of relay 2T, front contact of relay IS, terminal post I, wire 3'1, back contact 38 of relay TPR and to the C battery terminal. The opening of the back contact 35 when relay IS is picked up removes current from the heating element 22 of relay IT and. that relay quickly cools and its contact 23 is returned to its normal open position. The relay 2T is adjusted to operate its contact 53 at the expiration of 10 seconds as indicated on the drawing and, consequently, 10 seconds after the picking up of relay IS and the closing of the circuit for the heating element of relay 2T the contact 53 is operated and the stick relay 25 is energized, the pickup circuit for relay 2S including the contact 53, winding of relay 2S and the back contact 54 of the next succeeding stick relay 3S. The stick relay 2S on being picked up accomplishes four functions similar to the four functions recited in connection with the relay IS, and in addition it opens the stick circuit for the relay IS at its back contact 41 as already explained. The stick circuit for the relay 2S is the same as that traced for the relay IS up to wire 44 from thence the circuit includes front contact 51 of relay 28, the operating winding of the relay and the back contact 54 of the next succeeding stick relay 3S as will be understood by an inspection of the drawing. The heating circuit for the heating element 55 of the relay 3T is completed at the front contact 53 of relay 2S when that relay is picked up, while the circuit for the heating element 5| of the relay 2T is now open at the back contact 34 of relay 2S and this latter thermal relay 2T quickly cools and its contact 53 is restored to its normal open position. Hence, if a train consumes 40 seconds in passing through the timing section X-Y, the relay 2S is picked up and stuck energized prior to the time the train enters the operating section Y-Z. Each of the remaining thermal relays 3T to 9T, inclusive, is adjusted to operate its contact in. 10 seconds after current is applied to its heating element, Consequently. a traintravelling at the low speed of 13 miles per hour or less and consuming something over 110 seconds in advancing over the timing section, the stick relay SS is picked up and stuck energized prior to the time the train enters the operating section YZ. It is to be noted that a train travelling at 54 miles per hour consumes approximately 30 seconds in advancing through the timing section XY and thus for train speeds higher than 54 miles per hour none of the stick relays of the first time measuring means TMI is energized before the train enters the operating section and stops operation of the thermal relays by shunting the track relay ZTR. and opening its front contact 24. For train speeds between the low speed rate of 13 miles per hour and the speed of 5 miles per hour the thermal relays IT to 9T, inclusive, are successively operated and a particular one of the stick relays is picked up and retained energized over its stick circuit, the relay thus retained energized being in accordance with the speed of the train, and each stick relay being released when the next succeeding stick relay is picked up. That is to say, the first time measuring means TMI of the control mechanism CM is held at the position to which it has advanced during the time a train is moving through the timing section.

Referring now to the timing units D of the second time measuring means TME, the control of each of these units is similar in each case and it is then t that a description of the control of one sue Lit will suffice for an understanding of all. It is to be noted that the units ID to 9D are adiu: ed for different operating times, the operating time being progressively longer. Looking at the timing unit ID, an energizing circuit may be traced from the B battery terminal over back contact 2i of the circuit controlling armature ZTR-iii, wire 58, terminal post 2 of the control mechanism CM, wire 59, front contact of the stick relay IS, operating winding of the timing unit ID and thence to the 0 battery terminal. It follows that in the event the stick relay S of the first time measuring means TMI is picked up and held energized in response to a train passing through the timing section, current is suppiied to the operating winding of the first timing unit iD of the second time measuring means TM2 when the head end of that train enters the operating section and shunts the track relay In a similar manner, current is supplied to the operating winding of each of the timing units 2D to 9D, inclusive, if the stick relay S of the corresponding timing unit of the first time measuring means is picked up at the time the track relay ZTR is shunted. In other words, the timing units D of the second time measuring means are selectively controlled, the unit selected for operation being in accordance With the energized stick relay S of the first time measuring means TMI.

Each of the timing means D controls a normally closed contact interposed in the circuit network for the winding 9 of the interlocking relay IR. It will be recalled that each of the stick relays S of the first time measuring means controls a normally open contact interposed in the circuit network. The arrangement is such that the contact controlled by a timing unit D cooperates with the contact controlled by the corresponding S relay with the result that the network comprises a series of branch paths each of which inoiudes a normally open contact and a normally closed contact in series. Referring to the timing unit ID and the corresponding stick relay IS,

the circuit network can be traced from the B. battery terminal over back contact 2| of the circuit controlling armature ZTRZII, wire 58, terminal post 2, wire 59, front contact 60 of relay IS, back contact 6| of unit ID, wire 62, terminal post 3, wire 93, back contact H of track relay ZTR, wire 84, winding 9 of the interlocking relay IR and to the C battery terminal. It follows that the winding 9 of the relay IR is retained energized over the network subsequent to the shunting of the track relay ZTR and the opening of its front contact IE, if the stick relay IS has been picked up and its front contact 60 closed in the manner previously explained, and if the corresponding timing unit ID has not yet functioned to open its normally closed contact 6|. The relay IR is preferably made slightly slow releasing in order to retain its armature I2 lifted during the time the armatures of the track relay ZTR are moving from engagement with their front contacts to engagement with their back contacts.

In describing the operation of the apparatus, I shall consider the apparatus to normally occupy the position illustrated in the drawing and in which position the highway crossing signal W is inactive. I shall first consider the case where a train travelling at the maximum speed of miles per hour approaches the highway crossing from the left. This train requires approximately 20 seconds in moving through the timing section XY with the result that the thermal relay IT has not yet operated its contact 23 prior to the time the train enters the operating section Y-Z and discontinues the flow of current to the heating element 22 of relay IT by shunting the track relay ZTR and opening its front contact 24. Under these circumstances the winding 9 of the interlocking relay IR is deenergized when the track relay ZTR is shunted and the armature I2 is released at the end of the release period with the result that the signal W is set into operation very shortly after the train enters the operating section Y-Z. Since it requires slightly over 20 seconds for this train to pass through the operating section Y-Z, substantially 20 seconds operation of the signal W prior to the arrival of the train at the highway crossing H is efiected. When the rear of the train clears to the right of the crossing H, the track relay ZTR of the operating section is picked up and the winding 9 of the relay IR is reenergized and the operation of the signal W is stopped. I shall next assume that a train travelling at a little above 54 miles per hour approaches the highway crossing from the left. This latter train requires just a little less than 30 seconds to advance through the timing section and enter the operating section, and hence the thermal relay IT has not yet operated its contact 23 when the train enters the section 1-2 and shunts the track relay ZTR. Again, the winding 9 of reiay IR is deenergized and the signal W is set into operation very shortly after the train enters the operating section. This train moving at a little over 54 miles per hour consumes substantially 30 seconds in advancing through the operating section Y-Z with the result that the signal W is operated substantially 30 seconds prior to the arrival of the train at the crossing. Hence, for all speeds between 80 and 54 miles per hour the signal W is operated for a period which falls within the permissible limits of 20 to 30 seconds. 7

I shall next assume a train approaches the crossing at a speed a little less than 54 miles per hour with the result that the relay I S is picked up just prior to the time the train enters the operating section Y-Z, since this train consumes a little over 30 seconds in the timing section X-Y. Under this condition the winding 9 of the relay IR is retained energized following the shunting of the track relay ZTR by virtue of the circuit network, the network being completed over the contact Bl] of the relay IS and the contact 6| of the unit ID. The operating winding of the unit ID is now supplied with current over the circuit including the front contact 60 of the relay IS and thus it operates its contact BI at the expiration of 10 seconds with the result that the winding 9 is deenergized and the signal W set into operation substantially 10 seconds from the time the train first enters the operating section. That is to say, the starting of the operation of the signal W is delayed approximately 10 seconds for the train whose speed is a little less than 54 miles per hour. Since this train consumes a little over 30 seconds in moving through the operating section, the signal W is operated approximately 20 seconds prior to the arrival of the train at the crossing.

It is to be noted that the relay 42 is normally energized over .a simple circuit including the front contact I 6 of relay ZTR, wires 64 and B5, terminal post 8 of mechanism CM, wire I9 and winding of the relay to the C battery terminal. Furthermore, subsequent to the shunting of relay ZTR, this relay 42 is retained energized over the back contact 2| of the relay ZTR, the circuit network including contacts fill and SI, back contact II, Wires 54 and 65, terminal post 9, Wire III and winding of relay 42 to the C battery terminal, since the relay 42 is slow releasing in character and does not release when relay ZTR. is shunted. Following the operation of the timing unit ID and the opening of its contact 6 I the relay 42 is deenergized as well as the winding 9 of the relay IR and the 1 relay 42 is released at the end of its slow release period. The opening of the front contact 43 of relay 42 deenergizes the stick relay IS and that relay is released and in turn current is removed from the operating winding of the timing unit 1;

I D when the front contact 69 of relay IS is opened. It follows that the relay IS and the timing unit ID are returned to their normal condition following the setting of the signal W into operation.

I shall next assume a train travelling 30 miles per hour approaches the highway crossing from the left. This train requires substantially 54 seconds in advancing through the timing section X--Y with the result that the relays IT, 2T and 3T are successively operated and the stick relay 3S is picked up. With the relay 3S energized at the time the train enters the operating section and shunts the track relay Z'I'R, the winding 9 of the relay IR is retained energized over the path of the network which includes contact 66 of the timing unit 3D and contact 61 of the relay 38. This time there is a delay of 30 seconds in setting the signal W into operation since the unit 3D is adjusted to operate its contact 6'5 in 30 seconds.

The train travelling 30 miles per hour requires substantially 54 seconds to advance through the operating section and hence about 24 seconds operation of the signal W prior to the arrival of the train at the crossing is effected.

In the case of atrain moving at the low speed of 13 miles per hour and thereby consuming something over 110 seconds in advancing through the timing section, the thermal relays IT to 9T, inclusive, are operated and the stick relay SS is picked up. Under this condition a seconds de- ISO lay in starting the operation of the signal W is efiected since the winding 9 of the relay IR is now retained energized over the path of the circuit network which includes contact 68 of the timing unit 9D and front contact 69 of the relay 9S and since the operating time of the timing unit 9D is set at seconds. This slow moving train of a speed of 13 miles per hour takes something over seconds to advance through the operating section and hence the signal W is operated a little over 20 seconds prior to the arrival of the train at the crossing. It is clear that for all other speeds between 13 and 80 miles per hour .a similar operation is eilected with the result that at least 20 seconds and not more than 30 seconds operation of the signal W obtains for each train.

It is apparent that, if the permissible variation in the operating time was, for example, 20 to 40 seconds in place of 20 to 30 seconds as considered in the foregoing description, at considerable less number of individual timing units would be required and the control mechanism CM could be simplified accordingly.

In practicing my invention the timing units may all be assembled in a suitable case with terminal posts to which the external circuits .are connected. The control mechanism could thus be set up as a standard unit, and the setting of the timing units varied to fit the particular track and traffic conditions of the particular location at which it is to be used.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track intersected by a highway, at highway crossing signal located adjacent the intersection, a speed measuring means controlled by a train approaching a fixed point in the rear of the intersection to register the speed of the train, a time measuring device including a series of individual electroresponsive timing units, means governed by the speed measuring means to selectively control said timing units in accordance with the registered speed, means controlled by the train upon reaching said fixed point to energize the particular timing unit selected, and circuit means governed by said timing units for setting the signal into operation and rendered effective when the selected unit has operated.

2. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, a speed measuring means controlled by a train approaching a fixed point in the rear of the intersection to register the speed of the train, a time measuring means including a series of electroresponsive timing units with the successive units provided with progressively increasing operating times, means governed by the speed measuring means to selectively control said timing units in accordance with the registered speed, means controlled by the train upon reaching the fixed point to energize the particular timing unit selected, and circuit means governed by said timing units for setting the signal intooperation when the selected unit has operated.

'3. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, a speed measuring means controlled by a train approaching a fixed point in the rear of the intersection to register the speed of the train, a time measuring device including a series of individual timing units, means governed by the speed measuring means to selectively control said timing units in accordance with the registered speed, means controlled by the train upon reaching said fixed point to render active the particular timing unit selected, and circuit means governed by the timing units for setting the signal into operation and. rendered efiective when the selected unit has operated.

4. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, a speed measuring means controlled by a train approaching a fixed point the rear of the intersection to register the speed of the train, a time measuring device including a series of individual electroresponsive timing units with each unit provided with a predetermined distinctive operating time, circuit means controlled jointly by the train upon reaching the fixed point and by the speed measuring means. to energize a particular timing unit which is selected according to the registered speed, and other circuit means governed by the timing units for setting the signal into operation when the selected timing unit has operated.

5. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, controlling means for setting the signal into operation when a train approaching the intersection reaches a fixed point, a speed measuring means controlled by the train as it approaches the fixed point to register the speed of the train, a time measuring device including a series of individual electrorespo-nsive timing units, means governed by the speed measuring device to selectively control the timing units in accordance with the registeredv speed, means controlled by the train upon reaching said fixed point to energize the particular timing unit selected, and means governed by the timing units to render the controlling means inefiective to set the signal into operation until the selected timing unit has operated.

6. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, control- B ling means for setting the signal into operation when a train approaching the intersection reaches a fixed point, a speed measuring means controlled by the train as it approaches the'fixed point to register the speed of the train, a time measuring device including a series of individual electroresponsive timing units, means governed by the speed measuring device to selectively control the timing units in accordance with the registered speed, means controlled by the train upon reaching said fixed point to energize the particular timing unit selected, and a circuit network including a normally closed contact of each of the timing units in parallel for rendering the controlling means ineffective to set the signal into operation until the contact of the selected unit is operated.

'7. In combination, a stretch of railway track intersected by a highway, said track being divided into two track sections on one side of the highway, a highway crossing signal located adjacent the intersection, a speed measuring means controlled by a train occupying the more remote section to register the speed of the train, controlling means controlled by a train occupying the section nearer the crossing for setting the signal into operation, a time measuring device including a series of individual electroresponsive timing units, means governed by the speed responsive means to selectively control said timing units in accordance with the registered speed, means controlled by a train occupying the section nearer the crossing to energize the particular timing unit selected, and means governed by the timing units to render the controlling means ineffective to set the signal into operation until the selected timing unit has operated.

8. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, controlling means for setting the signal into operation when a train approaching the intersection reaches a fixed point, a first time measuring device controlled by the train to register the time consumed by the train in travelling a fixed distance in approaching said fixed point, a second time measuring device including a series of individual electroresponsive timing units, means governed by the first time measuring device to selectively control said timing units in accordance with the registered time, means cont-rolled by the train upon reaching the fixed point to energize the particular timing unit selected, and means governed by the timing units to render the controlling means ineffective to set the signal into operation until the selected timing unit has operated.

9. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, controlling means for setting the signal into operation when a train approaching the intersection reaches a fixed point, speed measuring means including a thermal relay and a stick relay, a circuit controlled by a train approaching the fixed point to energize the thermal relay, a pickup circuit for the stick relay including a contact operated by the thermal relay, a stick circuit for said stick relay to bridge around said operated contact, circuit means including a front contact of said stick relay for rendering the controlling means ineffective to set the signal into operation, and means controlled by the train upon reaching the fixed point and including a contact interposed in said stick circuit and operable after a predetermined time interval to operate the contact to open said stick circuit whereby said stick relay is released and the controlling means rendered effective to set the signal into operation.

10. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, controlling means for setting the signal into operation when a train approaching the intersection reaches a fixed point, speed measuring means comprising a series of individual timing units each of which includes a thermal relay and a stick relay, circuit means controlled by a train approaching said fixed point to successively energize said thermal relays, a pickup circuit for each stick relay including a contact operated by the associated thermal relay, a stick circuit for each stick relay to bridge around the contact of the associated thermal relay and including a back contact of the next succeeding stick relay and a wire common to all the stick circuits, a circuit network including front contacts of said stick relays in parallel for rendering the controlling means ineffective to set the signal into operation, and means controlled by the train upon reaching the fixed point a d ncluding a contact interposed in said common wire, and said means operable after a predetermined interval or time to operate the contact whereby whichever stick relay is picked up is released and the controlling means rendered effective to set the signal into operation.

11. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, controlling means for setting the signal into operation when a train approaching the intersection reaches a fixed point, speed measuring means comprising a series of individual timing units each of which includes a thermal relay and a stick relay, circuit means controlled by a train While travelling a given distance in approaching said fixed point to successively energize said ther mal relays, a pickup circuit for each stick relay including a contact operated by the associated thermal relay, a stick circuit for each stick relay including a back contact of the next succeeding stick relay, an electroresponsive time measuring device including a series of contacts operable at diiferent predetermined time intervals one such contact for each of said timing units, means controlled by the train upon reaching the fixed point to retain energized the stick relay last picked up and to energize said time measuring device, and a circuit network including said contacts of the time measuring device in parallel for rendering the controlling means ineffective to set the signal into operation until the contact of said device corresponding to the timing unit the stick relay of which is picked up is operated.

12. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, a control circuit for setting the signal into operation when a train approaching the intersection reaches a fixed point, a first and a second time measuring device each normally set at a given position, means controlled by the train to render the first device active to move away from said given position while the train travels a fixed distance preceding said fixed point, means controlled by the.

train upon reaching the fixed point to hold the first device at the point to which it has advanced and to render the second device active to move away from its given position, means controlled jointly by said two devices for rendering the control circuit ineffective to set the signal into operation until the second device has advanced and registers with said first device, and means including a relay governed by said control circuit effective to restore both of said devices to their" respective given positions upon said control circuit being made efiective to set the signal into operation.

13. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, a circuit network adapted at times to control the operation of the signal and comprising a plurality of parallel paths each of which includes a normally open contact and a normally closed contact in vice, means controlled by a train approaching a fixed point to the rear of the intersection to successively energize the units of the first device, and means controlled by the train upon reaching said fixed point to retain energized the last energized unit of the first device and to energize the selected unit of the second device.

14. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, a circuit network adapted at times to control the operation of the signal and comprising a plurality of parallel paths each of which includes a normally open contact and a normally closed contact in series, a first time measuring device including a plurality of individual timing units one for each of said parallel paths and which is effective when energized to close the open contact of that path, a second time measuring device including a plurality of individual timing units one for each of said parallel paths and which is effective when energized to open the closed contact of that path, means controlled by a train approaching a fixed point to the rear of the intersection to successively energize the units of the first device, means controlled by the train upon reaching the fixed point to retain energized the last energized unit of the first device, and other means controlled jointly by the train and by the unit of the first device thus retained energized to energize the unit of the second device associated with the same path as the energized unit of the first device.

15. In combination, a stretch of railway track intersected by a highway, a highway crossing signal located adjacent the intersection, a first time measuring means comprising a series of individual timing units each of which includes a thermal relay and a stick relay, circuit means controlled by a train in travelling a fixed distance in approaching the intersection to successively operate said timing units, stick circuit means including a contact operated when a train has traveled said fixed distance to retain energized the stick relay of the last unit operated, a second time measuring means comprising a plurality of individual timing units one for each unit of the first means, means controlled jointly by a train when it has traveled said fixed distance and by the stick relay which is retained energized to operate the corresponding unit of the second means, and a circuit network comprising a series of parallel paths each of which includes a front contact of a stick relay and a back contact of the corresponding unit of said second means, and said network effective at times to control said signal.

JAMES A. PARKINSON. 

